Plastics and chemicals group Borealis Agrolinz Melamine GmbH invested in two long-term and comprehensive revamp projects at Linz chemical park to increase availability and overall efficiency. Based on the final study conducted by Pörner in 2015/2016, Pörner was also commissioned with the “execution phase” of both projects in 2018.
This concerns the projects Pipe Rack Refurbishment (PRR) and MD Pipeline LTO. Both modernizations have now successfully been completed.
Revamped pipe racks
To extend the service life of the structures, the PRR project aimed to provide complete structural analyses for the existing pipe racks that have multiplied over decades.
The pipe rack structures – some of which had existed for more than 70 years – were documented, inspected and updated to meet current structural requirements. Reinforcement measures were drawn up and structural analyses for connections and joints (incl. nodal statics) were provided.
The Pörner team faced some particular challenges:
- The overlap with the other project being executed at the same time required a high degree of coordination. The new steam pipes affected a large part of the parallel-engineered pipe rack sections.
- Instead of welding, bolted connections were used wherever possible for safety reasons.
- The limited space on the existing, tightly built-up site was a challenge for Pörner’s structural engineers.
The smooth coordination of both projects ensured the best overall result thanks to the use of point clouds from laser scans. In times of the pandemic, it was possible to plan integrated without restrictions. An additional benefit of planning was the 3D model for the customer, which could always be adapted to the current project status.
Project PRR – Facts & Figures:
- Approx. 4,100 running meters of pipe rack structures were engineered
- A total of approx. 4,200 steel bars
- with a total tonnage of 125 t were installed.
- The structural analyses comprised over 22,000 pages.
Revamped steam network
The parallel project to the modernization of the pipe bridges was to standardize the operated medium-pressure steam networks (20 and 25 bar) and upgrade them to a redundant 25 bar medium-pressure steam system.
Since the recalculation of the 20 bar steam pipe ruled out its use as a 25 bar steam pipe, it was finally decided to completely replace the 20 bar steam pipe. The existing 25 bar steam pipe was integrated into the new system.
Accordingly, it was necessary to determine the changed load data of the new pipeline routing on the pipe racks and to check the steel structure and if necessary reinforce it – which was realized directly by Pörner Vienna’s structural engineers in the parallel project. To safeguard the original 20 bar steam consumers, pressure-reducing stations, and at various steam feed points, additional overpressure and temperature safeguarding devices were provided. Therefore, the project required not only mechanical but also EI&C planning, which Pörner Linz did as well.
In total, the replacement of the 20 bar steam pipe network required well over 300 new pipes and the structural analyses for a smooth TÜV acceptance were prepared. One of the complexities of both projects was that all construction and installation work was executed without interrupting operations. Scheduled plant shutdowns were used for tie-in works on pressurized pipes. Close and permanent coordination with the chemical site’s operations and the executing construction and installation companies was crucial for the success.
In December 2021, the execution phase was completed successfully and on time under the proven, cooperative overall project management of the customer Borealis and in partnership cooperation of Pörner with the other companies involved.
